Mineral oil composition



Patented Sept. 24,1946

2,408,103 MINERAL on. oomrosrrron Herschel G. Smith, Wallingiord. and Troy L.

v Cantrell, Lansdowne, Pa., and John G. Peters,

Audubon, N. J.,- assignors to Gulf Oil Corporation, Pittsburgh, Pa., a corporation of Pennsylv I v No Drawing. Application March 19'. 1945,

Serial .No. 583,659

Claims. 1 This invention relates to improved mineral oil compositions, and more particularly to improvedmineral oils and oil compositions each comprising a major amount of mineral oiland a minor amount of a new improvement agent, or mixture of agents, capable of imparting a plurality of useful, advantageous properties thereto; these improved oil compositions being useful and advantageous in protecting metals, both ferrous'and non-ferrous metals, from r'ust, corrosion and wear. It also includes methods of making such agents and improved oil compositions containing thesame. j j

As is well known, the simple straight mineral oils usually are deficient in one or more respects, for certain commercial uses and it is common practice to incorporate one or more additive? compounds in the oil to overcome the defect or defects thereof for certain uses. ious agents have been incorporated in oils to improve certain of their properties for particular or special uses requiring a superior oil. In general, such agents or additive compounds are known as improvement agents.

We have now discovered certain new improvement agents for mineral oils which are particularly advantageous in the commercial preparacompositions and other useful mineral oil compositions. Our agents can be readily incorporated in various mineral oils and oil compositions.

When incorporated therein, even in very small amounts, these agents markedly improve the rust preventive qualities thereof. Further, they are also capable of imparting other useful and advantageous properties to mineral oil and oil compositions, as more fully described post.

Our new and advantageous improvement agents for mineral oils and oil compositions are oil-soli=0 I v I wherein M is a divalent metal, such as calcium,

etc., R is an alkyl group containing from 8 to 22 carbon atoms and R ishydrogen or an alkyl group, advantageously a short chain alkyl roup. That is,.our improvement agents are substane Likewise, var- .tion of various lubricants, protective coating tially neutral divalent metal salts of ortho phthalamidic acids containing two alkyl groups attached to the nitrogen atom thereof, one being a hydroxylated alkyl group and the other a long 1 chain alkyl group, as shown by the above formula.

As a class. the above metal salts are excellent improvement agents for mineral oils and oil compositions and can be easily incorporated in such oil compositions, in proportions necessary for present purposes. All of these improvement agents are readily and markedly soluble in mineral oils, particularly naphthenic type oils. In deed, most of them are viscous oily liquids at ordinary temperatures and can be readily incorporated in parafllnic type mineral oils, as well as naphthenic and mixed type base oils. Again,

On the other hand, our new improvement agents are water-resistant compounds which are practically insoluble in water and aqueous solutions. That is, they have a combination of properties which render them particularly advanta geous for the purposes of this invention, as is shown more fully post.

Further, these improvement agents can be readily prepared by various methods,,- as described in our companion application Serial No. 608,100, filed July 31, 1945, wherein we claim these new oil-soluble metal salts and methods of making the same. As there described, our new improvement agents can be readily prepared, ad-

vantageously in situ in mineral oil, directly from divalent metal hydroxides, phthalic anhydride and secondary-aliphatic amines having the lollowing. formula:

, R-N-o-e-on wherein R represents hydrogen or an alkyl group and R represents an alkyl group containing from 8 to 22 carbon atoms. In turn, these secondary alkyl amines containing a hydroxyl group attached to one of the alkyl groups thereof can be readily prepared by reacting alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide and the like with primary alkyl amines having the following formula:

V H2N-CH2(CH2) n-CHS wherein n is a number between 6 and 18. Some of and other primary alkyl amines having the above formula. Any of the above primary fatty amines may be used with advantage in making the secondary amines useful for the present purposes, as all of them readily react with propylene oxide and similar alkylene oxides, as shown in our said companion application Serial No. 608,100. For instance, as there shown, monolauryl amine (primary dodecyl amine) is useful and advantageous. Likewise, primary hexadecyl amine (mono-palmityl amine) is also advantageous in preparing secondary aliphatic amines useful for the present purposes. Further, mixtures of such primary amines may also be employed, somewhat better products being obtained with mixed amines. For instance, one commercially available mixture of such primary fatty amines is the so-called cocoamine. As stated in the said copending application, commercial cocoamine has an average molecular weight of 210 and contains a major amount of lauryl amine admixed with minor amounts of homologues thereof. This commercial fatty amine may be employed with advantage in prethe primary alkyl amines of this generic class paring secondary aliphatic amines useful in making our improved oil-soluble polyvalent metal salts of ortho phthalamidic acids by the advantageous methods set forth in our copending application Serial No. 608,100.

Further, as shown in our said eopending application, in so preparing our agents from such.

secondary amines, phthalic anhydride and divalent metal hydroxide, those chemicals are reacted together and converted into new com-' pounds; they being chemically combined together in the molecular ratios necessary to produce our new substantially neutral oil-soluble divalentmetal salts having substantially the generic structure given ante. In doing so, we usually react said secondary amines with phthalic an hydride in substantially equimolecular amounts to form a monoamide of phthalic acid, namely, the desired N-alkyl, N-alkylol ortho phthalamidic acid, and then neutralize the residual acidity of that compound by reaction with lime, sumcient lime being employed to form substantially neutral lime salts thereof. In lieu of lime, other hydroxides of divalent metals may be employed such as magnesium hydroxide, barium hydroxide and the like. Further, is so preparing these metal salts, these reactions can be advantageously effected in the presence of sumcient mineral oil to dissolve the oil-soluble compound so obtained; the new improvement agents being formd in situ in the oil, as described and illustrated in our said companion application Serial No: 608,100.

Indeed, in the practice oithe present invention we usually prepare the desired metal salts in situ in mineral oil. The concentrated solutions of neutral metal salts in oil have certain advantages for the present purposes; they being themselves excellent improvement agents for lIIiparting rust preventive qualities and other advantageous properties to a wide range oi. commercial compositions, such as greases, waxes, petrolatum and petrolatum-like coatingcompositions,-as well as mineral oils and oil compositions.

The following examples illustrate various methods of preparing our improvement agents and improved compositions containing the same.

Example I.In this example, a substantially neutral calcium salt was prepared, in situ in mineral oil, directly from phthalic'anhydride, dodecyl propanol amine and hydrated lime; the, oil-soluble salt so prepared being a neutral calcium salt of N-dodecyl, propanol ortho phthalamidic acid and having the following formula:

The procedure in preparing this improvement agent was as follows: To 1640 grams of a '70 viscosity Txeas oil distillate were added 296 grams Gravity: A. P. I 18.3 Viscosity, S .U. V:

F 432 210 56.9 Ash as sulfate 5.58

It was a concentrated solution of the said neutral calcium salt and contained approximately 33 per cent by weight of said calcium salt. Nevertheless, it was a light mobile liquid at room temperature. This clearly shows the high solubility of our new metal salts in mineral oils.

That is, the foregoing example is typical and illustrative of certain embodiments of this invention. In other embodiments thereof, other secondary alkyl, alkylol amines can also be employed in making our improvement agents as stated ante. For instance, in Example I, other secondary amines such as dodecyl butanol amine, hexadecyl propanol amine and the like may be employed in lieu of dodecyl propanol amine. Fur.- ther, mixtures of such secondary alkyl, alkylol amines may likewise be employed with advan-'- tage, as illustrated in the following examples:

Example II.-This' example illustrates the preparation of a mixture of secondary amines which are useful in making our oil-soluble metal salts; this mixture of secondary alkyl alkylol amines being-typical and advantageous forthe present purposes and being prepared from propylene oxide and commercial cocoamine.

Into a suitable reaction vessel equipped with a reflux condenser and means for heating and agitating the charge there were charged 840 grams of commercial cocoamine and then 232 That is','the foregoing Examples I and III,- respectively, are typical and illustrative of our new Y improvement agents and methods of making the Then the reaction geneous clear, semi-viscous liquid comprising a mixture of secondary fatty propanol amines contaming a major amount of lauryl propanol amine. This mixture of secondary amines is useful and advantageous in preparing a wide variety of our new oil-soluble improvement agents. It readily reacts with phthalic anhydride to form ortho phthalamidic acid which in turn can be readily converted into various metal salts by reaction with divalent metal hydroxides.

The preparation of oneadvantageous improvement agent from thismixture of secondary fatty propanol amines is illustrated in the following example.

- Example IH.In this example, a substantially neutral calcium salt was prepared,-in situ in a light mineral lubricating oil, directly from phthalic anhydride, hydrated lime and the mixture of secondary amines obtained in Example II ante; the mineral oil being a 70 viscosity Texas oil distillate having the following properties:

Gravity: i. P. I 26.0

Viscosity, S. U. V.:

100 F sec 210 36 In preparing this advantageous improvement agent, the following procedure was employed.

To 1780 grams of the mineral oil were added 298 grams of phthalic anhydride and '74 grams of hydrated lime. Ii'ie lime, phthalic anhydride oil slurry was then stirred vigorously while 536 grams of the secondary amines were added ove the course of one hour. During this time the temperature was'maintained at 150 F. and after the lime and phthalic anhydride had gone into solution, the temperature was raised to 280 F.

and the oil solution was filtered. 1

The filtrate soobtained is also an excellent improvement, agent for the present purposes. It was an oily mobile liquid at room temperature and had the following properties: 7

Gravity: A.P.I 18.3 Viscosity, SUV:

Ash as su 5.1

It'was a concentrated solution of substantially neutral calcium salts of the ortho phthalamidic was readily miscible with various mineral oils and oil compositions and was directly soluble in most mineral oils in a manner effective for the present purposes. In particular, this improvement agent is useful and advantageous as an additive compound in preparing improved motor oils and like lubricants. It is also advantageous in preparing other improved oil compositions useml in protecting metals against abrasion and corrosion.

same which are advantageous in certain embodiments of this invention. In other embodiments thereof, we may also employ various other divalent metal hydroxides and secondary amines containing an alkylol group in making our improvement agents, as stated ante. For instance, the hydroxides of magnesium, barium and other divalent metals may be used in Examples I and III, ante, in lieu of lime, to produce still other advantageous improvement agents.

In fact, by the present invention a wide range of improvement agents-can be readily prepared in the genericpractice thereof. All of them are readily soluble in commercial mineral oils and oil compositions in the proportions required to effect the desired improvements. Indeed, a wide range of improved anti-rust lubricants can be readily prepared by incorporating minor amounts In general, such improved anti-rust lubricants efiectively protect ferrous and non-ferrous metals against rusting and corrosion, even when exposed to salt water and other severe conditions.

For instance, advantageous anti-rust lubricants can be prepared by dissolving in light lubricating oils small amounts of the products obtained in Examples I and III ante.

, Further, the concentrated solutions of the calcium salts in oil, obtained in Examples I and III, are directly useful as rust preventive coating compositions for metals. They are substantially non-corrosive to both ferrous and non-ferrous metals. When applied to such metals, they tightly adhere to the metal forming a protective coat ing thereon which is resistant to water and aqueous liquids and fully protects the metal against rust or corrosion, even when exposed to the most drastic conditions. That is, our new oil-soluble metal salts are very potent rust preventive compounds. Accordingly, they can also be compounded with various other materials in preparing a wide range of protective coating compositions for metals. In particular, they are readily solublein various hydrocarbon oils, particularly mineral lubricating oils. Further, they are also readily miscible with waxes, petrolatum and greases, as well as oil compositions.

Thus, our new improvement agents, such as obtained in Examples I and 'III, are useful in preparing a wide range of compositions having exceptional rust preventive properties; they being particularly advantageous in preparing im proved anti rust lubricants-to which they impart further advantageous properties as shown post. Such improved lubricants can be readily obtained by incorporating small amounts of our improvement agents in mineral lubricating oils, greases, petrolatum and the like. For instance, the improvement agents obtained in Examples I and properties of such oil. Forexample, the'mineral lubricating oils containing'from 0.1 to 1.0 percent by weight of such improvement agents have increased resistance to oxidation and deteriora-' tion, as well as improved rust preventing or corrosion preventing properties.

The following examples illustrate the prepare-.-

tion of such improved lubricants and methods of making the same:

Distilled water, 122 F., 12 daysS tcel Example IV.--In this example one such advantageous anti-rust lubricant containing 0.1 per cent of the substantially neutral calcium salt of N-dodecyl propanol ortho phthalamidic acid, dissolved in a commercial mineral. lubricating oil. was prepared as follows:

Into asuitable vessel, equipped with means for agitating thecharge, there were charged 100 parts of the commercial lubricating oil and then 3 parts by weight of the filtrate obtained in Example I were added to the oil with stirrin The stirring was continued until the improved agent was uniformly and homogeneously blended with the oil.

The properties of the improved oil and the base oil employed in making the same were as follows:

gg Base oil Gravity: A. P. I..- 30.0 Viscosity, SUV;

100 F 102. 8 r 102. 8 210 38. 7 38, 7. Neutralization No Nil. Nil

Corrosion test, Method 412, Gulf gfi strip: 7

Appearance Bright Rusted Area rusted, per cent 0 100 Synthetic sea water, 122 F., 12 days- Steel strip:

Appearance Area rusted, per cent Bright Rusted The said corrosion tests employed were standard tests for determining the rust-preventive properties of commercial mineral oils and oil compositions. In such tests the procedure is as follows: I

Thirty-six cc. of the oil to be tested and 4 cc. of distilled water are placed in a 1" x 6" P.yrex test tube, a polished steel strip is inserted in the oil-water mixture, and 2000 cc. of humid air per hour are bubbled through the mixture from a point near the bottom of the tube, so as to provide aeration and mixing of the oil and water; the apparatus-being set in a water bath maintained at 122 F. (50 C.) and the-original water level in the tube maintained by additions of fresh water every 24 hours. This test is continued for v12 days after which the test strip is removed and inspected.

A like test is also employed, for which straight sea water (or synthetic sea water) is used in-.

stead of distilled water. This variation is a far more severe corrosion test, the corrosion effects being usually ten or more times those for fresh water, other testing conditions being the same. r As shown by the test data ante, our improved anti-rust oil had outstanding rust-preventive properties and satisfactorily passed said test, particularly the drastic test with sea water.

Bese oil v.

In view of their outstanding anti-rust prolierties and other advantageous properties shown ante, our improvement agents are useful and advantageous in a. wide range of commercial oil compositions. They may also be incorporated in minor amounts in other types'of oils, such as turbine oils, instrument oils, electric motor oils and other high quality lubricants where it is important to protect metal surfaces from rust and corrosion, as well as adequate lubrication thereof under service conditions.

For example, improved turbine oils can be readily prepared by dissolving 0.03 to 3.0 per cent of our improvement agents, such as obtained in Examples I and III, in any of the commercial turbine oils. The preparation of one such improved turbine oil is illustrated in the following example: I

Example V.In this example, an improved turbine oil was prepared by dissolving 0.03 per. cent of the filtrate obtained in Examplem, in a. suitable w'ell-refined mineral lubricating oil. The improved lubricant contained 0.01 per cent of the substantially neutral calcium salts of the phthalamidic acids obtained in said Example III.

The properties of this improved lubricant and the base oil employed in making the same were as follows:

Properties gfi Base oil Gravity, A. P. I 31. 0 31.7 Viscosity, SUV:

' 297 295 Flash, 00, F. 425 425 Fire, 00, 470 470 Pour, +6 +5 Color, NPA 2. 25 2. 25 Neutralization No 0. 02 0. 02

The above improved turbine oil, with this markedly low'dosage of our highly effective corrosion preventive agent, and without the addition of any supplemental corrosion preventive agent;

successfully passed without any traces of rusting, the above described steel strip corrosion test at a temperature of 122 F. for a test period of twelve days. Furthermore, it also passed the tentative test of the American Society for testing materials designated as ASTM D 665-42T, which is a similar test, but involves continuous mechanical stirring.

- of a mixture of 90 per cent by volume of the oil and 10 per cent of distilled water at F. for 48 hours. After the termination of this test there was no trace of corrosion for the standard steel corrosion strip. Before the addition of the small amount of the anti-corrosion agent like tests by the two methods on the base oil both failed, with marked rusting, which began to appear in less than 12 hours from the start of each test.

In general, our improvement agents have I proven to be quite satisfactory addition agents for turbine oils; particularly for compounded turbine oils of higher viscosity types, such as are preferred for marine service, the preferred amount of the agent ranging from 0.01 per cent. to 0.04 per cent according to our regular practice, although somewhat larger amounts of additive agent can be used without reducing the quality of the oil in other respects. For an actual marine service test, an improved turbine oil testing 300 viscosity at,100 F. containing 0.01 per cent by weight of our improvement agent satisfactorily lubricated the turbines of an ocean going vessel under severe operating conditions. After trial of'200 days, the lubricating system of the turbine and auxiliary equipment were all free of rust or like corrosion. Further, the non-rusting quality of the improved turbine oil was found to be practically unchanged; 9, sample of the used oil, when tested for anti-rust and lubricating properties, was found to have retained-its desired properties in all respects. The results from this run, along with others for similar operating conditions, demonstrate that theimproved turbine oil is satisfactorily stable under service conditions and capable of operating satisfactorily for prolonged service in ocean going vessels; in particular, our improved turbine oils retain this important quality when exposed to oxidizing conditions or contact with water for long periods; that is, they retain this quality when exposed to oxidizing conditions of use, 'as well as the leaching effects of water for extended periods, due to the Commer- Improved oil cial oil gravity; 26 1;} gr. Li). gal 00 F Carbon residue, per cen t Copper strip test, 212 F., 3 hrs" Neutralization No Iodine No., Mod. Hanns As shown by the above tabulation of properties, the incorporation of this improvement agent in useful and advantageous as a lubricant in various types of turbines. When subjected to the various standard tests used in evaluating commercial turbine oils it successfully passed all of them, even the most drastic ones.

For instance, this improved turbine oil is very resistant to emulsiflcation. Further, when emul-' sions. are formed they readilybreak. This is clearly shown by the data obtained in standard emulsion tests; the results obtained being as follows:

Emulsion test, 180 F.,

Method 330.13, Govt: Distilled water 40-40-0 (4) 1% salt solution 40-40-0 (3) The above data clearly shows the superior qualithe commercial turbine oil, in the amounts nece s- W sary to impart marked rust preventive qualities thereto, did not substantially change any of the above properties thereof. However, the markedly improved rust-preventive qualities of the improved oil so obtained is clearly shown by'the results obtained when our improved turbine oil was subjected to the above mentioned standard corrosion test. The data obtained in such test were as follows:

Commer- Improved oil cial oil Corrosion test, ASTM D 665-42 T, distilled water 10%, 140 F., 48 lam-Steel strip Appearance Area rusted: er nt..-

Corrosion test, ethod 412, Gulf, distilled water, 122 F., 12 days-Steel strip:

Appearance .Area rusted: per cent i.

Bright Rusted o 100 Bright 0 Rusted 1 ties of our improved turbine oils in this respect; these qualities being important in the satisfactory lubrication of turbines. I

Likewise, our improved turbine oils are resistant to foaming when agitated in the presence of air or gases. Their superiority in this respect is clearly shown by the results obtained when subjected to certain standard foaming tests; the

test data obtained being as follows:

Foamingtest, Method 413, Gulf:

550 R. P. M., 15 min.-

Vol. 011 and foam: v01. oil, 77 F 1.00

After standing 1 hr 1.00 900 R. P. M.:

Vol. oil and foam: Vol.oil, 77 F 1.12

After standing 1 hr 1.00

Air bubbling foam test:

Method 435, Gulf- Vol. oil and foam: Vol. oil, 77' F 1 0 Vol. oil and foam: Vol. oil, F 1 0 Vol. oil and foam: Vol. oil, F 1 0 Further, in addition to the above advantageous properties, namely, the marked resistance to foaming and emulsification, and marked anticorrosion qualities, our improved turbine oils have other superior properties advantageous in lubricating tunbines. For instance, they have excellent lubricating qualities as evaluated by the standard "Falex wear test. When so evaluate the test data obtained is as follows:

Falex wear test:

' 500 110. gauge load, 15 min.-

, Wear: No. of teeth 0 "Gauge load at seizure: Lbs 1100 Also, in addition to their excellent lubricating qualities, our improved turbine oils are markedly resistant to oxidation and deterioration. For instance, the improved turbine oils shown in Examples .V and VI successfully passed various standard oxidation tests. In one such test, the Sligh oxidation test, the improved turbine oil of Example V had a Sligh oxidation number of 7.

In other words, a plurality of advantageous properties can be imparted to turbine oils by incorporating our new improvement agents therein. Likewise, similar improvements can be obtained inother types of lubricants by incorporating our new agents in various oils and oil compositions.

For example, our new agents are also useful and advantageous in preparing improved motor oils for lubricating automotive, aviation and Diesel engines. Such improved oils can be readily prepared by incorporating a few per cent of these improvement agents in a suitable mineral lubricating oil; usually 0.3 to 3.0 by weight -of the oil. The compounded oils so obtained have imaaoaios wherein It represents an alkyl group containing 8 to carbon atoms. Such oil-soluble compoundscan be readily produced from the reaction or inter-action of a polyvalent metal hydroxide,

properties even under severe operating conditions.

In particular, this invention relates to improved lubricating oils containing a multi-functional improvement agenthaving antioxidant and other advantageous properties such as high film strength, Moreover, the lubricating oils to which our inhibitor is added are capable of retarding the formation of all forms of gum, resins, carbon, and varnish-like materials which are usually formed on the pistons and rings of internal combustion engines. In addition to the property of being able to inhibit the formation of products phthalic anhydride and primary alkyl amines, ail-'- vantageously in situ in mineral oil. as described and illustrated in our prior application.' As there shown. the improvement agents so obtained imp rt a plurality of valuable properties to mineral oils and oil compositions and are advantageous forsuch purposes.

The oil-soluble calcium phthalyl alkyl amide compounds employed in our prior application are substantially neutral calcium salts of a mono capable of corroding sensitive metallic bearings normally found in internal combustion engines or other metals contacted with the oil, all oils containing our improvement agents and minor proportions of water or salt water are inhibited against corrosion tendencies. proved lubricating compositions comprising a major amount of a petroleum lubricating oil and is, our improved oil compositions are markedly- That is, our im- 1 alkyl amide of phthalic acid, as shown by the above generic formula. Theyare alsodesignated as calcium N-alkyl amido phthalates, as stated in our prior application. However, as is evident from the above formula, these oil-soluble salts are substantially neutral divalent metal salts of ortho phthalamldic acids containing a long chain alkylgroup attached to the nitrogen thereof. which carries a reactive hydrogen attached thereto.

The oil-soluble salts employed in the present invention are substantially neutral divalent metal salts of ortho-phthalamidic acid containing an alkylol group attached to the nitrogen atom thereof, in addition to the long chain alkyl group atresistant to water and aqueous solutions, as well as stable against oxidation.

Accordingly, in the broad practice of this invention a wide range of improved mineral oil compositions can be readily prepared, including excellent protective coating compositions, as well as improved anti-rust lubricants. Thus, broadly, this invention relates to improved mineral oil compositions containing minor amounts of substantially neutral divalent metal salts of N-alkyl, alkylol ortho phthalamidic acids, as a new and advantageous improvement agent; the amount of such improvement agent being sumcient to impart thereto the advantageous properties desired. In general, our improved oil compositions usually contain from 0.03 to 10.0 per cent by weight of such improvement agents dissolved in the mineral oil.

This application is a continuation-in-part of our prior application Serial No. 516,968, filed and claimed improved mineral oil compositions containing a minor amount of oil-soluble calcium phthalyl alkyl amide compounds having the following formula:

tached thereto. Thus, so to speak, our new improvement agents are alkylol derivatives of the improvement agents set forth in our prior application. Indeed, they can be prepared by reacting said neutral calcium phthalyl alkyl amides with propylene oxide and similar alkylene oxides; thereby substituting an alkylol group for the hydrogen attached to the nitrogen atom in the ortho phthalamidic salt shown in our prior application.

That is, we have now found that by substituting an alkylol group for the hydrogen attached to the nitrogen atom of the ortho phthalamidic acid salts shown in our prior application, Serial No. 516,968, now U. S. Patent No. 2,378,442, we obtain a new and different class of improvement agents or polyvalent metal salts which in addition to having greater solubility in mineral oils also have other modified properties which render them particularly useful as improvement agents for mineral oils and oil compositions; these improvements being in part due to the presence of the alkylol group in the molecule of our new im provement agents. The present application is broadly directed to improved mineral oil compositions containing these new improvement agents.

What we claim is:

1. An improved mineral oil composition comprising a major amount of a mineral oil and a minor amount of an oil-soluble divalent metal salt of N-alkyl, alkylol ortho phthalamidic acid, said metal salt having the following formula I 0 o G 0 wherein .M is a divalent metal, R is an allq'l group containing 8 to 22 carbon atoms and R is hydrogen or an alkyl group, and the amount of said metal salt being sufllcient to impart corrosion- 13 inhibiting properties to the improved oil composition.

2. The composition of claim 1 wherein the said mineral oil composition contains from 0.01 to 10.0 per cent by weight of said improvement agent dissolved in the mineral oil.

3. The improved composition of claim 1 wherein the said oil-soluble metal salt is a calcium salt.

4. The improved composition of claim 1 wherein the said oil-soluble metal salt is a substantially neutral calcium salt of N-dodecyl propanol ortho phthalamidic acid.

5. An improved mineral oil composition comprising a, major amount 01' a mineral lubricating 011 containing dissolved therein from 0.01 to 10.0 per cent by weight of an oil-soluble calcium N- Patent No. 2,408,103.

IHERSOHELI c. SMITH ET AL.

following formula:

wherein R represents hydrogen or an alkyl group, and n is a, number between 6 to 20, said improvement agent being substantially neutral and readily soluble in mineral oils.

CHEL G. SMITH. TROY L. CANTRELL. JOHN G. PETERS.

.Qertificate of Correction September 24, 1946.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Column 3, line 43, before the word Further insert the following paragraph* Processes of making secondary N-propanol N-alkyl amines by reacting equimole'cular proportions of propylene oxide and a long cha1n primary aliphatic amine are claimed in our copending application, Serial No. 640 ,128 filed January 9, 1946, as a continuation-in-part of the present application.

line 63, for the word is. read in; line 67, for formd read formed; column 4 line 28, for Txeas read Terms; and that the said Letters Patent should be read w1th these corrections therein that the same may conform to the record of the case in the Patent Signed and sealed this 17th day of December, A. D 1946.

LESLIE FRAZER,

First Assistant Oommz'ssz'oner of Patents. 

